Review of Impala 27

The hull is made of fibreglass. Generally, a hull made of fibreglass requires only a minimum of maintenance during the sailing season. And outside the sailing season, just bottom cleaning and perhaps anti-fouling painting once a year - a few hours of work, that's all.

The interior is like many other boats made of mahogany.
The boat is equipped with 5 berths, a galley and toilet facility.
Note: the boat has also been sold to be self-made/-interiored, which means that the quality of each boat may vary.

The boat equipped with a fractional rig. A fractional rig has smaller headsails which make tacking easier, which is an advantage for cruisers and racers, of course. The downside is that having the wind from behind often requires a genaker or a spinnaker for optimal speed.

The Impala 27 is equipped with a fin keel. The fin keel is the most common keel and provides splendid manoeuvrability. The downside is that it has less directional stability than a long keel.

The keel is made of iron. Many people prefer lead keel in favour of iron. The main argument is that lead is much heavier than iron and a lead keel can therefore be made smaller which again result in less wet surface, i.e. less drag. In fact iron is quite heavy, just 30% less heavy than lead, so the advantage of a lead keel is often overstated. As the surface of a fin type keel is just a fraction of the total wet surface, the difference between an iron keel and a lead keel can in reality be ignored for cruising yachts.

Impala 27 can enter most marinas as the draft is just about 1.65 - 1.75 meter (5.41 - 5.71 ft) dependent on the load. See immersion rate below.

The boat is typically equipped with an inboard diesel engine.

What is Capsize Screening Formula (CSF)?

The capsize screening value for Impala 27 is 2.33, indicating that this boat would not be accepted to participate in ocean races.

What is Theoretical Maximum Hull Speed?

The theoretical maximal speed of a displacement boat of this length is 6.4 knots. The term "Theoretical Maximum Hull Speed" is widely used even though a boat can sail faster. The term shall be interpreted as above the theoretical speed a great additional power is necessary for a small gain in speed.

The immersion rate is defined as the weight required to sink the boat a certain level. The immersion rate for Impala 27 is about 145 kg/cm, alternatively 814 lbs/inch.
Meaning: if you load 145 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 814 lbs cargo on the boat it will sink 1 inch.

What is Motion Comfort Ratio (MCR)?

The Motion Comfort Ratio for Impala 27 is 14.6 - 15.2.

Comparing this ratio with similar sailboats show that it is more comfortable than 18% of all similar sailboat designs. This is a comfort value significantly below average.

What is L/B (Length Beam Ratio)?

The l/b ratio for Impala 27 is 2.69.

Compared with other similar sailboats it is more spacy than 86% of all other designs. It seems that the designer has chosen a significantly more spacy hull design.

What is a Ballast Ratio?

The ballast ratio for Impala 27 is 42%.

This ballast ratio shows a righting moment that is higher than 58% of all similar sailboat designs. A righting moment (ability to resist heeling) just above average.

What is Displacement Length Ratio?

The DL-ratio for Impala 27 is 190 which categorizes this boat among 'light racers'.

73% of all similar sailboat designs are categorized as heavier. A light displacement requires less sailarea and has higher accellerations.

What is SA/D (Sail Area Displacement ratio)?

The SA/D for Impala 27 with ISO 8666 reference sail is 20.4, with a 135% genua the SA/D is 23.9.

The SA/D ratio indicates that it is faster than 92% of all similar sailboat designs in light wind.

The Impala 27 has more rig than 86% of all similar sailboats, which indicates that the boat is significantly overrigged.

What is Relative Speed Performance?

The Relative Speed Performance for Impala 27 is 93

The relative speed performance is 93 which means that a it is faster than 93% of all similar sailboat designs.

When buying anti-fouling bottom paint, it's nice to know how much to buy. The surface of the wet bottom is about 25m² (269 ft²).
Based on this, your favourite maritime shop can tell you the quantity you need.

Note: If you use a paint roller you will need more paint than if you use a paintbrush.

Dimensions of sail for fractional rig.

Are your sails worn out? You might find your next sail here: Sails for Sale

If you need to renew parts of your running rig and is not quite sure of the dimensions, you may find the estimates computed below useful.

This section shown boat owner's changes, improvements, etc. Here you might find inspiration for your boat.

Do you have changes/improvements you would like to share? Upload a photo and describe what to look for.

We are always looking for new photos. If you can contribute with photos for Impala 27 it would be a great help.

If you have any comments to the review, improvement suggestions, or the like, feel free to contact us. Criticism helps us to improve.

[Ref 1]: ISO 8666 Small craft — Principal data.
[Ref 3]: ISO 12215-5 Small craft — Hull construction and scantlings.